Goals from Abdoulaye Meite, Chris Brown (penalty) and man-of-the-match Mark Duffy saw Rovers run out easy winners over a poor Charlton side, whose spirit evaporated once Lawrie Wilson was sent off late in the first half.
Sharp made his second home debut for Doncaster, almost two years to the day since he last donned a Rovers shirt before a big-money move to Southampton, as manager Paul Dickov named an unchanged starting XI.
Charlton boss Chris Powell handed a first-ever start to teenage defender Harry Lennon as he made three changes following their FA Cup win at Huddersfield, with Yann Kermorgant and Jordan Cousins also recalled.
Chances were at a premium early on, with Sharp’s blocked effort, following a mistake by Johnnie Jackson, the only worthwhile piece of attacking intent as both sides huffed and puffed their way through the opening 25 minutes.
Just past the midway mark, though, Rovers finally created an opportunity and took advantage to open the scoring, with Meite scrambling home his first goal for the club, seconds after Bongani Khumalo had almost broken the deadlock.
A James Husband free-kick reached Khumalo at the back post and he poked the ball back across goal, only to see a combination of the woodwork and desperate defending deny him. The ball was cleared to Duffy who cracked in a low shot, which Ben Alnwick saved with his legs only for Meite to tap in the rebound from less than a yard out.
The pendulum swung further Rovers’ way 10 minutes later as Charlton full-back Wilson was shown a straight red card by referee Paul Tierney for upending Sharp from behind in the box. Brown held his nerve to coolly send Alnwick the wrong way from the spot.
Alnwick again saved with his legs from James Coppinger, before Sharp stung his palms with a vicious effort from 18 yards as the half came to a close.
With a man advantage, Rovers controlled the opening exchanges of the second half but struggled to break down a stubborn Charlton defence, which now had Richard Wood in its ranks after replacing Cedric Evina at the break.
Duffy and Coppinger were running the show for Dickov’s side and from a looping Coppinger cross, Gabriel Tamas volleyed into the side netting as he was given licence to push forward.
Duffy’s excellence was rewarded after 67 minutes as he increased Doncaster’s lead with a curling effort from just inside the box to leave no way back for the visitors, who had long run out of ideas.
Coppinger then had a shot blocked and a Duffy free-kick was saved by Alnwick before he set up Sharp, who spurned the chance to make it a dream return to the Keepmoat.
Substitute Dave Cotterill, on for Sharp, fired narrowly wide and fellow replacement Alex Peterson saw a speculative effort hit the bar as Rovers pocketed an easy three points.